Optimizing Energy Performance

Nov. 17, 2008

The Gaia Napa Valley Hotel and Spa, American Canyon, Calif., is one of three Gaia hotels owned by the Atman Hospitality Group, Inc. (Atman), San Francisco, which is a member of the U.S. Green Building Council (USGBC). Owner and founder Wen-I Chang grew up in Taiwan in an environment that nurtured union with nature.

Inspired by the design concepts of Mickey Muennig, a student of Frank Lloyd Wright, the plans for the 133-room hotel were drawn by the firm of Todd Jersey Architecture, Berkeley, California, which specializes in green services, including LEED® administration. By using natural lumber certified by the Forest Stewardship Council (FSC); ultra-quiet; energy-efficient HVAC systems with environmentally friendly refrigerant; low VOC paints; solar panels that provide 12 percent of the hotel's electrical needs; low-flush toilets; and low-flow showerheads and tubular skylights that allow natural light into the lobby, hallways and conference rooms, the hotel earned LEED certified Gold status. An interior plaza features a swan lagoon, which is fed by rain and recycled storm water. An educational, real-time energy kiosk in the lobby shows guests how the hotel's various systems work and indicates the daily water and electricity savings compared to ordinary hotels.

The quest for LEED
When searching for the ideal HVAC system to match his LEED certification aspirations, Chang contacted Neil Riley, president, Riley & Associates, Walnut Creek, California. Chang wanted Gaia's HVAC system to be as environmentally friendly and innovative as the rest of the hotel's sustainable design. The HVAC system had to be extremely quiet, provide the utmost in energy efficiency, and have the outdoor units installed out of sight. He also wanted a smart system that offered simultaneous cooling and heating.

Riley knew of the right system for meeting the demands of Chang's vision. He described Mitsubishi Electric HVAC Advanced Products Division's expertise and industry leadership in LEED-type projects around the world. He listed the many benefits of the CITY MULTI R2-Series Variable Refrigerant Flow Zoning (VRFZ) system that would help earn LEED points. He told Chang about the unique INVERTER-driven Variable Frequency Drive compressor, which provides highly responsive cooling and heating performance in each guest room. He mentioned the ultra-quiet performance from both the outdoor and indoor units. He showed Chang how the wall-mounted indoor units-with sound ratings as low as 32 dB(A)-would be installed unobtrusively in each room.

Chang realized the advantages of CITY MULTI systems in building a case for LEED certification for his new hotel, so he instructed Riley to proceed with the engineering plans.

LEED certification commissioning
For a project to be LEED certified, building owners need help from professionals specializing in supervising and facilitating contractor-based commissioning services. For Gaia Napa Valley Hotel & Spa, Riley turned to Steve Guttmann, PE, LEED AP, principal, Guttmann & Blaevoet Consulting Engineers (G&B), San Francisco.

Guttmann was familiar with CITY MULTI VRFZ systems and was key to assisting Penry and Orson Poon, HVAC contractor, Orson Mechanical, Inc., Hayward, California. He was especially helpful in specifying the appropriate LEED procedures for issues such as how to measure the correct refrigerant amount.

To be LEED certified Gold, a project must receive between 39 and 51 points from the USGBC. The Gaia USGBC LEED-NC Report, dated June 4, 2007, achieved a total of 43 points. Twenty-three percent of the overall "Credit Scorecard" came from the "Energy & Atmosphere" section of the report. "Six of these 10 points were earned under the ‘Optimize Energy Performance' section," Guttmann explained. "That's a very high performance rating and CITY MULTI systems played a significant role in achieving that score."

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